Ram for circumferential crimping



July 16, 1963 D. DlBNER RAM FOR CIRCUMFERENTIAL CRIMPING Filed May 2,1960 FIG.3A

FIG IA PRIOR ART co m 9 LL an l E? u m 9 m n- INVENTOR.

DAVID DIBNER AGENT therebetween.

United States Patent 3,097,683 RAM FOR CIRCUMFERENTIAL CRIMPING DavidDihner, Wilton, Conn, assignor to Burndy Corporation, a corporation ofNew York Filed May 2, 1960, Ser. No. 26,379 4 Claims. (Cl. 153-1) Thisinvention relates to the metal working art, and more particularly to thedesign of dies for the compression of malleable metal tubes on a centralcore.

It is commonplace to attach a malleable metal connector to a conductorby compressing the connector with the conductor inserted therein betweena ram. and a nest die to obtain a full circumferential crimp around theconnector. It is difiicult, however, to manufacture the ram and nest dieto a close mating tolerance. Consequently, a flash is formed in theconnector at the juncture of the ram and nest die about the connector.

It is, therefore, an object of this invention to provide a ram of noveldesign, which can be conveniently manufactured and will provide a veryclose fit between the nest die and ram at their juncture about theconnector.

A feature of this invention is a pair of mating dies including a pair ofprojections disposed on the inner surface of one die adjacent the otherdie and adapted to project into said inner surface of said other diewhen said dies are closed.

These and other objects and features of this invention will become moreapparent by reference to the following description taken in conjunctionwith the accompanying drawings, in which:

FIG. 1a is an end view in cross section of a ram and a nest die, inseparated relationship, illustrating the prior art;

FIG. lb is an end view in cross section of the ram and the nest die ofFIG. 1a in closed relationship;

FIG. 2a is an end view in cross-section of a ram and a nest die, inseparated relationship, embodying this invention;

FIG. 2b is an end view in cross section of the ram and the nest die ofFIG. 2a in closed relationship;

FIG. 3a is an end view in cross-section of a pair of dies in separatedrelationship, illustrating an alternative embodiment of this invention;and

FIG. 3b is an end view in cross-section of the dies of FIG. 3a in closedrelationship.

Referring now to FIG. 1a, the prior art arrangement is seen to consistof nest die 1 and a ram 2 which are adapted to circumferentiallycompress a connector 3. In mass production it is very difiicult toproduce a ram and nest die pair having a close fit, e.g.

Consequently, when the circumferential crimp is made, as shown in FIG.1b, the ram does not precisely mate with the nest die at their junctureabout the connector, and a flash is formed at 4 and 5.

As will be seen in FIG. 2a, ram 21 includes a longitudinal slit 22 and aspring steel shield 23 mounted to the rams working end by suitablemeans, such as the pinning of suitable tabs 24 and 25, to thebifurcation 26 and 27 created by the slit. The shield may be made withsharp edges 28 and 29, and being of spring steel, will conform to thewidth of the nest die 30, with the edges scraping the walls of the die.Thus when the connector 31 is circumferentially crimped, as shown inFIG. 2b, a very close fit will be obtained between the shield and thenest die, and no flash will be formed. The slit 22 permits thebifurcations to spread apart slightly when 3,097,683 Patented July 16,1963 the crimp is being made and to apply pressure to the edges 28 and29 of the shield.

Referring now to FIG. 3a, a pair of abutting dies 41, 42 is here shown.One of the dies, as 42, has mounted therein a U shaped spring 43. Thespring may be fastened to the die 42 by any convenient means tofacilitate removal of a connector after crimping. For example,mechanical means such as integral tabs 24, 25 (shown in FIGURES 2a and2b) or a suitable bonding agent applied between the spring and the dieface, may be employed. When the dies are closed, the legs of the U arebent by the mating die, as 41. In the fully closed position, the ends ofthe U just abut each other, as shown in FIG. 3b. In operation theconnector 44 is placed within the U spring 43 and the dies are closed.Spring 43 closes around the connector, preventing the formation of flashbetween the dies.

The invention has thus been described but it is desired to be understoodthat it is not confined to the particular forms or usages shown anddescribed. The same being merely illustrative, and that the inventionmay be carried out in other ways without departing from the spirit ofthe invention, and therefore, the right is broadly claimed to employ allequivalent instrumentalities coming within the scope of the appendentclaims, and by means of which objects of this invention are attained andnew results accomplished, as it is obvious that the particularembodiments herein shown and described are only some of the many thatcan be employed to obtain these objects and accomplish these results.

I claim:

1. A pair of mating dies for crimping a therebetween inserted connector;each of said dies having an inner sur- (face forming a cavity includinga pressure applying face; an arcuately formed leaf spring member mountedadjacent the face of one of said dies and having the distal ends thereofbiased radially outward to resiliently bear against and slide along theother die inner surface, to obstruct the gap between adjacent surfacesof the dies as they are moved toward mating position; said leaf springmember being adapted to resiliently conform to the adjacent surface ofthe therein inserted connector as said dies are closed into full matingrelationship and to resume its undeflected arcuate form when the diesare parted.

2. A pair of dies according to claim 1 wherein said leaf spring memberis substantially U-shaped, the distal ends of the legs thereof beinginwardly bent to facilitate flexure as the dies are closed.

3. A pair of dies according to claim 1 wherein the distal ends of theleaf spring member have beveled edges adapted to maintain smooth beveledcontact with the inner surface of the other die as the dies are movedinto full mating relationship.

4. A pair of dies according to claim 1 wherein one die is a ram and theother is a nest; said ram including a bifurcation in a plane includingthe longitudinal axis of the inserted connector for permitting slightspreading of said ram along said bifurcation when crimping the saidconnector.

References Cited in the file of this patent UNITED STATES PATENTS1,774,386 Lard Aug. 26, 1930 2,759,256 Bergan Aug. 21, 1956 2,802,257Holtzapple Aug. 13, 1957 2,878,854 Batcheller Mar. 24, 1959 FOREIGNPATENTS 757,376 Great Britain Sept. 19, 1956

1. A PAIR OF MATING DIES FOR CRIMPING A THEREBETWEEN INSERTED CONNECTOR;EACH OF SAID DIES HAVING AN INNER SURFACE FORMING A CAVITY INCLUDING APRESSURE APPLYING FACE; AN ARCUATELY FORMED LEAF SPRING MEMBER MOUNTEDADJACENT THE FACE OF ONE OF SAID DIES AND HAVING THE DISTAL ENDS THEREOFBIASED RADIALLY OUTWARD TO RESILIENTLY BEAR AGAINST AND SLIDE ALONG THEOTHER DIE INNER SURFACE, TO OBSTRUCT THE GAP BETWEEN ADJACENT SURFACESOF THE DIES AS THEY ARE MOVED TOWARD MATING POSITION; SAID LEAF SPRINGMEMBER BEING ADAPTED TO RESILIENTLY CONFORM TO THE ADJACENT SURFACE OFTHE THEREIN INSERTED CONNECTOR AS SAID DIES ARE CLOSED INTO FULL MATINGRELATIONSHIP AND TO RESUME ITS UNDEFLECTED ARCUATE FORM WHEN THE DIESARE PARTED.